) Journal of the Asiatic Society of Bengal. [N.S., XTX, 1923.) 
maturity. The heart-shaped muscular impression is 40 to 45 
mm. across and being of a very pale buff colour stands out 
clearly from the white. nacreous interior of the valves. The 
upper, outer surface of one of the valves has evidently been 
attached at one time to some rough surface on which cir ripedes 
of the genus Balanus were already growing. Later, the shell 
had broken free again carrying the remains of the barnacles 
with it. According to Dr. Annandale who has_ kindly 
examined the specimens, the species represented is probably 
Baianus amphitrite, Darwin, which ranges from the Miocene 
(Aquitanian) to the present time. 
‘EXPLANATION OF PLATE. 
(The figures represent specimens delineated about two-thirds 
of the natural size.) 
Ostrea gry phoides, Schlotheim. 
Fig. 1. Adult example showing the internal characters of the 
lower valve 
Fig. 2. Another adult example showing the internal charac- 
ters of the upper valve. 
The specimens were obtained from an excavation 
Swallow Lane, Calcutta and presented to the Geological Survey 
of India by Mr. J. H. de C. Ballardie (1923). 
